kitman



Aug. 7, 1951 l. l. KITMAN 2,563,174

THERMAL CIRCUIT BREAKER Filed oct. s, 195o 1, Fzty. 3.

nnentor Isaac [[(z'zman Patented Aug. 7, 1 951' Isaac I. Kitman., Pittsburg'h,fPa.,l assigner to, Julia Kitman, Pittsburgh, Pa.

I jjAppiicatioiroetcter"3, 195o, seri'ai 510,188,131

@3.1% gw... This invention relates to an-electrio circuit breaker, and` important objectsy and? advantages thereof are-to provide a-fcrcuit-breaker of the character described,-4 'which is Vdesigned and in-'f' tended 4to ysupersedea-fuse'plug of the conventional type commonly used *in branchv 'circuits carrying the smallerr currents, lwhichfwill functionautomaticallylto lbreakthe circuit when the current strength reaches a certain predeterminedvalue, which maybe-reset for repeated/usa'which is simple in its construction and arrangement, durable andvecientin its use, positive in its action, and comparatively economical in its manufacture andfuse. V V' With the foregoing and other objects in' view which will 4appear yas the vdescription proceeds, the invention residesini-the novel construction, combination, and arrangement-of parts herein specifically described and illustrated in the accompanying drawing, Ibut it is to be understood that changes inthe ,tormproportions and details of construction'mayberesortedto that come Within the .iscope-:ofithesclaim :hereunto appended.

In the drawing where like numerals'of!refer.-A

ence designate corresponding parts throughout the several views;

Figure 1 is a side elevationalview, partly"'in'b cross section, of the improved: electricY circuitbreaker, with the embodied control mechanism in the operative position.

Figure 2 is a similar view, with the control mechanism in the inoperative position.

Figure 3 is a top plan view of the device.

Referring in detail to the drawing, the improved electric circuit-breaker comprises a hollow plug body I, including a top cover 2, which latter is xed to the plug body by cementing, or in any other suitable manner. The lower exterior portion of the plug body is surrounded by a. fixed metallic thread shell 3, and the bottom 4 of the plug body carries a xed contact pin 5 disposed centrally of the bottom.

The plug body I and the top cover 2 are constructed of any suitable insulating material, and the assembly of the plug body and top cover, together with the embodied thread shell 3 and contact pin 5, provide a plug structure which has a general contour identical to the conventional type of fuse plug, and which is designed and intended to be screwed into the conventional type of electrical socket.

A thermostatically controlled switch 6 is mounted in the plug body I, and` comprises a pair of vertically opposed contact members 1 and 8. The lower contact member I is carried by claim. y(o1. zooi-iis) a lContact bracket 9, which is fixed to the contactl pin'i'; 1' The upper l contact member 8 is carried on theflower' ,face offtheouter end of a horizon# tally k'disposed contactbar I0. The contact bar has atapere'd inner' endl I, and 'is pivotally con# nected by a pivoting pin I2 to the lower end of a supporting lbracket I'3; The latter "is secured to and depends from thetop cover'z;

.A spiral ,compression spring .'I4 is connected with thesupportin'g 'bracket I3 and with the outer end of the contactliba'r lll, and-normally functions to shift andliol'd saidY contact 'bar' `to an angularposition fror'n'thev horizontal to openl the' switch', as clearly shownin Figure 2. The' angular s'l'liftable' movement' ofthe" contact bar" form'edi'n the supportl is limited'by ashoulder .f5 bracket 1'3, M l y A push'button 'IE'is mountedfor `verticalmovement in aV centrally disposed opening I1 in the topcover 2. A spirals'pring I'Bismounted in the opening Il and surrounds-the pus'h'button 'The action of l,the spring. ,I8 vnollmally tends 'to shift' the'push button to .its upwardk .positionin the" opening I'l.

manually actuated switch I9 isv mounted in tlfi'e'plugv 'body I, and 'comprises a .pair of vertically opposed contact members "20 and 2I. "Ih'"y upper contact member"2i's rcarri'e'd'lo'y the top cover 2, and the lower contact member 2I is carried by a bimetallic latch arm 22.

The bimetallic latch arm 22 is thermostatically actuated, and has its upper end secured to the lower end of the push button I5. The latch arm is normally vertically disposed in the plug body I, and carries a i-lxed tapered latching element 23 on the inner side of the lower end portion thereof. The latching element normally engages the tapered end I I, of the contact bar I9, for holding the latter in the normal horizontal position against the pull of the spring I4, to maintain the thermostatically actuated switch t in the closed position, as shown in Figure l.

A flexible conductor 24 connects the inner end of the contact bar Ill with the lower end of the latch arm 22, and a flexible conductor 25 connects the upper end of the latch arm with the thread shell 3 of the plug body. It will here be noted that either or both of the conductors 24 and 25 may be constructed of material that will fuse to break the electric circuit when the curl rent strength reaches a predetermined value.

When the improved electric circuit-breaker is screwed into an electric socket in the manner of an ordinary fuse plug, which it supersedes, the circuit is completed through the contact pin 5,

the contact bracket 9, the closed switch 6, the contact bar I0, the conductor 24, the latch arm 22, the closed switch I9, the conductor 25, and the thread shell 3. Under normal conditions the switches 6 and I9 are always closed to maintain the circuit, by the engagement of the contact bar I9 by the latching element 23.

The construction and operation of the bimetallic latch arm 22 is such that if the current strength of the circuit reaches and exceeds the predetermined value, the latch arm will be thermostatically actuated to release the latching element 23 from the tapered end I I of the contact bar I0, whereby the latter will be shifted by the action of the spring I4 to open the switch 6 and thereby break the circuit.

To reclose the circuit, the push button I6 is depressed to lower the latching element 23 so 4 economically employed for the purpose and in the manner herein set forth.

What I claim is:

An electric circuit-breaker of the class described, comprising the combination of hollow plug body including a top cover, a thread shell surrounding the lower portion of said body, a contact pin secured in the bottom of said body, a thermostatically controlled switch mounted in ysaid body, a manually controlled switch mounted in said body. a push button shiftably mounted in said cover, a spring mounted on said button that the latter will reengage the tapered end II of the contact bar I0. Upon release of the push button, the spring I8 will elevate the again normal latch arm 22' and cause the latching element 23 to reengage the contact bar and shift the latter to the normal horizontal position to close the switch 6 and thereby complete the circuit.

'Due to the inherent resiliency of the latch arm 22, and to the tapers of the contact bar end II of the latching element 23, the reengagement of the latter with said end II is readily effected by snap action.

When the push button I6 is depressed to reclose the switch B, in the manner stated, the switch I9 is opened for safety purposes, as the circuit is not closed until pressure upon the push button is removed to cause the closing of the switch I9 by the action of the spring I8. The construction and arrangement of the switch I9 limits the upward movement of the push button in the top cover opening II, and thereby obviates the possibility of holding a closed circuit by exerting suicient upward pull manually on the push button to prevent the normal thermostatic operation of the switch 6 to break the circuit when required for safety.

` The present invention provides a most durable and efficient device of its kind, which may be cheaply manufactured and successfully and for normally maintaining the latter in the upward position, a contact bracket secured to said pin and being connected with said thermo- --statically controlled switch, a supporting bracket carried by said cover, a contact bar pivotally connected with the lower end of said supporting .bracket and being connected with said thermopair of contact members being carried by said cover, and the other of said contact members being carried by said arm. and means formed on said supporting bracket for limiting the shiftable movement of said bar, a conductor connecting said bar with said arm, and a conductor connecting one of said pair of contact members with said shell.

ISAAC I. KITMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Kitman Oct. 4, 1949 Number 

